1. Technical Field
The present invention relates generally to head assemblies used in data storage devices, and more particularly to the air bearing surface on the slider affixed to the transducer suspension system.
2. Related Art
Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computer system will generally not operate.
The basic hard disk drive model includes a storage disk or hard disk that spins at a designed rotational speed. In actuator arm is utilized to reach out over the disk. The arm carries a head assembly that has a magnetic read/write transducer or head for reading/writing information to or from a location on the disk. The transducer is attached to a slider, such as an air-bearing slider, which is supported adjacent to data surface of the disk by a cushion of air generated by the rotating disk. The transducer can also be attached to a contact-recording type slider. In either case, the slider is connected to the actuator arm by means of a suspension. The complete head assembly, e.g., the suspension and head, is called a head gimbal assembly (HGA).
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly space at known intervals across the disk. When a request for a read of a specific portion or tract is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over to specific track location in the head writes the information to the disk.
Over the years, the disk and the head have undergone great reductions in their size. Much of the refinement has been driven by consumer demand for smaller and more portable hard drives such as those used in personal digital assistants (PDAs), MP3 players, and the like. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that). Advances in magnetic recording are also primary reasons for the reduction in size.
This continual reduction in size has placed steadily increasing demands on the technology used in the HGA, particularly in terms of power consumption, shock performance, and disk real estate utilization. One recent advance in technology has been the development of the femto slider, which is roughly one-third of the size and mass of the older Pico slider, which it replaces; over the past 23 years, slider size has been reduced by a factor of five, and mass by factor nearly 100.
These smaller sliders have substantially smaller surface areas, which generally increases the difficulties associated with achieving and maintaining a suitable fly height. Suitable fly height is particularly important to maintain because when a slider is flying higher than normal, the read/write performance is degraded. As mentioned above, this problem of maintaining suitable fly height is particularly egregious with smaller sliders such as femto sliders. As a result, because crown sensitivity directly affects fly height, concern for low crown sensitivity increases with growing market demands of smaller sliders. However, it has proven very difficult to find an appropriate design for the air bearing surface of a slider that significantly meets the needs imposed by current demand.